Area Forecast Discussion
Issued by NWS Aberdeen, SD
Issued by NWS Aberdeen, SD
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370 FXUS63 KABR 082319 AFDABR Area Forecast Discussion National Weather Service Aberdeen SD 619 PM CDT Sat Jun 8 2024 .KEY MESSAGES... - There is a 50 to 80% chance of showers and thunderstorms Monday afternoon through Tuesday morning. Some storms along and west of the Missouri River may become strong to severe Monday afternoon and evening. - Above normal temperatures will return Wednesday-Friday of next week, with highs mainly in the 80s. There is a possibility of areas reaching 90 degrees on Wednesday (50-80% chance), mainly over central SD. && .UPDATE... Issued at 617 PM CDT Sat Jun 8 2024 No changes to the forecast this evening. Update to aviation discussion below... && .SHORT TERM /THIS EVENING THROUGH SUNDAY NIGHT/... Issued at 319 PM CDT Sat Jun 8 2024 Overall, looking at pretty quiet conditions through the short term period. The light showers/sprinkles over the southwest CWA from earlier today have finally been reduced quite a bit in areal coverage under this expansive mid-level deck down that way. Surface high pressure stays in place through Sunday, making way for mostly dry conditions and fairly light winds. Will have to watch western SD on Sunday as a few CAMs indicate shower/thunderstorm potential across the High Plains, with perhaps some of this spilling as far east as the far southwest CWA. Have dry conditions going now, but something to watch. Otherwise, looking at mild temperatures for Sunday, with highs in the 70s to near 80 degrees. && .LONG TERM /MONDAY THROUGH SATURDAY/... Issued at 319 PM CDT Sat Jun 8 2024 Clusters agree pretty well with a shortwave moving in over the Northern Plains Monday through Tuesday along with a 850mb/sfc low skirting across southern Canada and northern ND/MN. GEFS seems to be the quickest with the progression of this system. The high will shift east early Monday and return flow ahead of this system will help dewpoints rise into the 50s, with areas across central SD rising into the mid to upper 50s to lower 60s Monday afternoon and evening. Temps in this area will rise into the upper 70s to lower to mid 80s as well. Probability of CAPE>1000 j/kg is 10-20% west of our CWA, per EC ENS, and GEFS around 10-20% around and west of the Mo River during peak heating hours. East of here instability drops off significantly. Bulk shear will be out of the west between 20-30kts. Ensemble means shows precip moving in and pushing west to east across the CWA (again GFS being the quickest) and continuing through Tuesday morning/afternoon (model depending) before ending west to east, as the low tracks east. Latest NBM matches well with the ensembles showing pops of 20-60% around and west of MO River through Monday afternoon, increasing to 60-80% over the entire CWA between 00Z-12Z Tuesday with lingering 20- 30% pops through Tuesday morning east of the James River. With only this marginal instability over central SD, the SPC has put a marginal risk (1/5) for strong to severe storms Monday afternoon and evening mainly over Rapid`s WFO with western portions of Corson and Dewey in this coverage. I would not be surprised if they expanded it further east around the Mo River area if the atmosphere is more like what the GEFS was showing. Even after sunset, a LLJ will keep the forcing for general tstorms through the night into early Tuesday as the system tracks east. A quick ridge aloft and high moves in behind the system for the rest of Tuesday bringing dry weather and temps ranging in the mid 70s to the lower 80s. Our attention then turns to Wednesday with overall zonal flow aloft with a possible shortwave from 700-surface pushing west to east with stronger winds aloft. Models agree on this but still some variability between the ensembles on intensity and timing. Return flow on PVA side of trough (over the eastern Dakotas Wednesday afternoon/evening) will raise dewpoints in the upper 50s to low 60s as temps will be quite warm in the 80s to the lower 90s potentially. This will help prime the atmosphere as daytime heating occurs. Prob of CAPE>1000 j/kg differs quite a bit between the EC Ens/GEFS with EC ranging from 20% to pockets of 50% where GEFS is much more bullish with probs 40-80% east of the Mo River and prob over 2000 j/kg between 20-50%. GFS also has 40-55kt shear forecasted as well and mid level lapse rates 6-7C. So all of this put together and if everything lines up through the atmosphere, this could bring a risk for stronger storms. However, it is still a bit early to nail down the specifics as we are seeing a difference instability wise and exact setup between models as mentioned. SPC and machine learning severe guidance does indicate a Day 5 15% severe risk for areas east of the Mo River, which does not happen too often around here so it will be something to watch. Right now NBM pops are a general 25-40% Wednesday afternoon and evening. Beyond this, the pattern remains active with several chances of moisture for the end of the week into the weekend as temps remain above average through Friday. && .AVIATION /00Z TAFS THROUGH 00Z SUNDAY/... Issued at 617 PM CDT Sat Jun 8 2024 Terminals KABR,KATY,KPIR,KMBG VFR conditions for all terminals. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. && $$ UPDATE...Connelly SHORT TERM...TMT LONG TERM...MMM AVIATION...Connelly